Vasilis Stavrou
Athens University of Economics and Business
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Publication
Featured researches published by Vasilis Stavrou.
ubiquitous intelligence and computing | 2013
Miltiadis Kandias; Vasilis Stavrou; Nick Bozovic; Lilian Mitrou; Dimitris Gritzalis
Addressing the insider threat is a major issue in cyber and corporate security in order to enhance trusted computing in critical infrastructures. In this paper we study the psychosocial perspective and the implications of insider threat prediction via social media, Open Source Intelligence and user generated content classification. Inductively, we propose a prediction method by evaluating the predisposition towards law enforcement and authorities, a personal psychosocial trait closely connected to the manifestation of malevolent insiders. We propose a methodology to detect users holding negative attitude towards authorities. For doing so, we facilitate a brief analysis of the medium (YouTube), machine learning techniques and a dictionary-based approach, in order to detect comments expressing negative attitude. Thus, we can draw conclusions over a user behavior and beliefs via the content the user generated within the limits a social medium. We also use an assumption free flat data representation technique in order to decide over the users attitude and improve the scalability of our method. Furthermore, we compare the results of each method and highlight the common behavior and characteristics manifested by the users. As privacy violations may well-rise when using such methods, their use should be restricted only on exceptional cases, e.g. when appointing security officers or decision-making staff in critical infrastructures.
workshop on privacy in the electronic society | 2013
Miltiadis Kandias; Vasilis Stavrou; Nick Bozovic; Dimitris Gritzalis
Insider threat is a major issue in cyber and corporate security. In this paper we study the psychosocial perspective of the insider via social media, Open Source Intelligence, and user generated content classification. Inductively, we propose a prediction method by evaluating the predisposition towards law enforcement and authorities, a personal psychosocial trait closely connected to the manifestation of malevolent insiders. We propose a methodology to detect users holding a negative attitude towards authorities. For doing so we facilitate the use of machine learning techniques and of a dictionary-based approach, so as to detect comments expressing negative attitude. Thus, we can draw conclusions over a user behavior and beliefs via the content the user generated within the limits a social medium. We also use an assumption free flat data representation technique in order to decide over the users attitude. Furthermore, we compare the results of each method and highlight the common behavior manifested by the users. The demonstration is applied on a crawled community of users on YouTube.
new technologies, mobility and security | 2014
Dimitris Gritzalis; Vasilis Stavrou; Miltiadis Kandias; George Stergiopoulos
Modern business environments have a constant need to increase their productivity, reduce costs and offer competitive products and services. This can be achieved via modeling their business processes. Yet, even in light of modellings widespread success, one can argue that it lacks built-in security mechanisms able to detect and fight threats that may manifest throughout the process. Academic research has proposed a variety of different solutions which focus on different kinds of threat. In this paper we focus on insider threat, i.e. insiders participating in an organizations business process, who, depending on their motives, may cause severe harm to the organization. We examine existing security approaches to tackle down the aforementioned threat in enterprise business processes. We discuss their pros and cons and propose a monitoring approach that aims at mitigating the insider threat. This approach enhances business process monitoring tools with information evaluated from Social Media. It exams the online behavior of users and pinpoints potential insiders with critical roles in the organizations processes. We conclude with some observations on the monitoring results (i.e. psychometric evaluations from the social media analysis) concerning privacy violations and argue that deployment of such systems should be only allowed on exceptional cases, such as protecting critical infrastructures.
trust and privacy in digital business | 2014
Vasilis Stavrou; Miltiadis Kandias; Georgios Karoulas; Dimitris Gritzalis
Business process modeling has facilitated modern enterprises to cope with the constant need to increase their productivity, reduce costs and offer competitive products and services. Despite modeling’s and process management’s widespread success, one may argue that it lacks of built-in security mechanisms able to detect and deter threats that may manifest throughout the process. To this end, a variety of different solutions have been proposed by researchers which focus on different threat types. In this paper we examine the insider threat through business processes. Depending on their motives, insiders participating in an organization’s business process may manifest delinquently in a way that causes severe impact to the organization. We examine existing security approaches to tackle down the aforementioned threat in enterprise business processes and propose a preliminary model for a monitoring approach that aims at mitigating the insider threat. This approach enhances business process monitoring tools with information evaluated from Social Media by examining the online behavior of users and pinpoints potential insiders with critical roles in the organization’s processes. Also, this approach highlights the threat introduced in the processes operated by such users. We conclude with some observations on the monitoring results (i.e. psychometric evaluations from the social media analysis) concerning privacy violations and argue that deployment of such systems should be allowed solely on exceptional cases, such as protecting critical infrastructures or monitoring decision making personnel.
ACM Computing Surveys | 2018
Dimitris Gritzalis; Giulia Iseppi; Alexios Mylonas; Vasilis Stavrou
Organizations are exposed to threats that increase the risk factor of their ICT systems. The assurance of their protection is crucial, as their reliance on information technology is a continuing challenge for both security experts and chief executives. As risk assessment could be a necessary process in an organization, one of its deliverables could be utilized in addressing threats and thus facilitate the development of a security strategy. Given the large number of heterogeneous methods and risk assessment tools that exist, comparison criteria can provide better understanding of their options and characteristics and facilitate the selection of a method that best fits an organizations needs. This article aims to address the problem of selecting an appropriate risk assessment method to assess and manage information security risks, by proposing a set of comparison criteria, grouped into four categories. Based upon them, it provides a comparison of the 10 popular risk assessment methods that could be utilized by organizations to determine the method that is more suitable for their needs. Finally, a case study is presented to demonstrate the selection of a method based on the proposed criteria.
international conference on e business | 2013
Miltiadis Kandias; Lilian Mitrou; Vasilis Stavrou; Dimitris Gritzalis
Social media and Web 2.0 have enabled internet users to contribute online content, which may be crawled and utilized for a variety of reasons, from personalized advertising to behaviour prediction/profiling. In this paper, our goal is to present a horror and a success story from the digital world of Social Media, in order to: (a). present a political affiliation profiling method, the Panopticon method, in order to reveal this threat and contribute in raising the social awareness over it. (b). describe an insider threat prediction method by evaluating the predisposition towards law enforcement and authorities, a personal psychosocial trait closely connected to the manifestation of malevolent insiders. The experimental test case of both methodologies is an extensive Greek community of YouTube users. In order to demonstrate our cases, we performed graph theoretic and content analysis of the collected dataset and showed how and what kind of personal data can be derived via data mining on publicly available YouTube data. As both methodologies set user’s privacy and dignity at stake, we provide the reader with an analysis of the legal means for each case, so as to effectively be prevented from a privacy violation threat and also present the exceptional cases, such as the selection of security officers of critical infrastructures, where such methodologies could be used.
international conference on security and cryptography | 2013
Miltiadis Kandias; Lilian Mitrou; Vasilis Stavrou; Dimitris Gritzalis
Computers & Security | 2017
Miltiadis Kandias; Dimitris Gritzalis; Vasilis Stavrou; Kostas Nikoloulis
Computers & Security | 2015
Vasilis Stavrou; Dimitris Gritzalis
International Journal of Social Network Mining | 2017
Miltiadis Kandias; Lilian Mitrou; Vasilis Stavrou; Dimitris Gritzalis